Acids, bases, and neutral substances are part of our daily lives. It is present in the food we eat to the products we use. This chapter helps us understand their properties, natural indicators, and how neutralization plays an important role. The following MCQs will test your knowledge and understanding of these concepts.
MCQ Questions for Class 7 Science Chapter 2 Exploring Substances: Acidic, Basic, and Neutral with Answers
Question 1: Which of the following tastes sour?
a) Soap
b) Lemon
c) Baking soda
d) Salt
Answer:
b) Lemon — Lemon tastes sour due to the presence of citric acid.
Question 2: Which substance is basic in nature?
a) Vinegar
b) Soap
c) Lemon juice
d) Tamarind
Answer:
b) Soap — Soaps are basic in nature.
Question 3: Which indicator turns red in acids and blue in bases?
a) Methyl orange
b) Turmeric
c) Litmus
d) Phenolphthalein
Answer:
c) Litmus — Litmus turns red in acids and blue in bases.
Question 4: Which of these is a natural indicator?
a) Hydrochloric acid
b) Litmus
c) Sodium hydroxide
d) Ammonia
Answer:
b) Litmus — Litmus is a natural indicator obtained from lichens.
Question 5: Which of the following is neutral?
a) Vinegar
b) Sugar solution
c) Soap solution
d) Baking soda
Answer:
b) Sugar solution — Sugar solution is neutral in nature.
Question 6: Which acid is present in vinegar?
a) Lactic acid
b) Acetic acid
c) Citric acid
d) Oxalic acid
Answer:
b) Acetic acid — Vinegar contains acetic acid.
Question 7: Which of the following is used as an antacid?
a) Hydrochloric acid
b) Baking soda
c) Sulphuric acid
d) Vinegar
Answer:
b) Baking soda — Antacids like baking soda neutralize excess stomach acid.
Question 8: Which indicator turns yellow in bases?
a) Phenolphthalein
b) Turmeric
c) Methyl orange
d) Litmus
Answer:
b) Turmeric — Turmeric turns yellow in bases.
Question 9: Which of these is an acid found in tamarind?
a) Acetic acid
b) Tartaric acid
c) Lactic acid
d) Citric acid
Answer:
b) Tartaric acid — Tamarind contains tartaric acid.
Question 10: Which of these is basic in nature?
a) Hydrochloric acid
b) Lime water
c) Vinegar
d) Lemon juice
Answer:
b) Lime water — Lime water (calcium hydroxide) is basic.
Question 11: Which indicator is colorless in acid and pink in base?
a) Litmus
b) Methyl orange
c) Phenolphthalein
d) Turmeric
Answer:
c) Phenolphthalein — Phenolphthalein is colorless in acid and pink in base.
Question 12: Which of the following is an acid found in curd?
a) Acetic acid
b) Citric acid
c) Lactic acid
d) Oxalic acid
Answer:
c) Lactic acid — Curd contains lactic acid.
Question 13: Which of the following is NOT an acid?
a) Acetic acid
b) Citric acid
c) Sodium hydroxide
d) Hydrochloric acid
Answer:
c) Sodium hydroxide — It is a base, not an acid.
Question 14: Which acid is found in oranges?
a) Citric acid
b) Acetic acid
c) Lactic acid
d) Oxalic acid
Answer:
a) Citric acid — Oranges contain citric acid.
Question 15: Which is a neutral solution?
a) Lemon juice
b) Distilled water
c) Soap solution
d) Vinegar
Answer:
b) Distilled water — Pure water is neutral.
Question 16: Which acid is present in tomato?
a) Lactic acid
b) Oxalic acid
c) Citric acid
d) Acetic acid
Answer:
b) Oxalic acid — Tomato contains oxalic acid.
Question 17: Which of these is alkaline?
a) Baking soda
b) Tamarind
c) Lemon juice
d) Vinegar
Answer:
a) Baking soda — Baking soda is alkaline in nature.
Question 18: What is the effect of acid on blue litmus?
a) Turns red
b) Turns yellow
c) Turns pink
d) No change
Answer:
a) Turns red — Acids turn blue litmus red.
Question 19: Which acid is found in spinach?
a) Citric acid
b) Oxalic acid
c) Lactic acid
d) Acetic acid
Answer:
b) Oxalic acid — Spinach contains oxalic acid.
Question 20: Which of these neutralizes stomach acidity?
a) Hydrochloric acid
b) Baking soda
c) Vinegar
d) Citric acid
Answer:
b) Baking soda — It is an antacid.
Question 21: Which acid is found in grapes?
a) Citric acid
b) Tartaric acid
c) Lactic acid
d) Acetic acid
Answer:
b) Tartaric acid — Grapes contain tartaric acid.
Question 22: Which of the following is NOT a natural indicator?
a) Litmus
b) Turmeric
c) Methyl orange
d) Red cabbage
Answer:
c) Methyl orange — It is a synthetic indicator.
Question 23: Which solution turns phenolphthalein pink?
a) Acidic solution
b) Basic solution
c) Neutral solution
d) Sugar solution
Answer:
b) Basic solution — Bases turn phenolphthalein pink.
Question 24: Which acid is found in sour milk?
a) Acetic acid
b) Lactic acid
c) Citric acid
d) Oxalic acid
Answer:
b) Lactic acid — Sour milk contains lactic acid.
Question 25: Which of the following is a strong base?
a) Sodium hydroxide
b) Vinegar
c) Lemon juice
d) Citric acid
Answer:
a) Sodium hydroxide — NaOH is a strong base.
Question 26: What does turmeric turn in a basic solution?
a) Yellow
b) Red
c) Blue
d) Pink
Answer:
b) Red — Turmeric turns red in a basic solution.
Question 27: Which acid is used in car batteries?
a) Hydrochloric acid
b) Sulphuric acid
c) Nitric acid
d) Acetic acid
Answer:
b) Sulphuric acid — Car batteries use sulphuric acid.
Question 28: Which of the following is NOT an acid-base indicator?
a) Litmus
b) Phenolphthalein
c) Sodium hydroxide
d) Turmeric
Answer:
c) Sodium hydroxide — It is a base, not an indicator.
Question 29: Which is a strong acid?
a) Hydrochloric acid
b) Acetic acid
c) Citric acid
d) Lactic acid
Answer:
a) Hydrochloric acid — HCl is a strong acid.
Question 30: Which base is used in making soaps?
a) Sodium hydroxide
b) Vinegar
c) Acetic acid
d) Citric acid
Answer:
a) Sodium hydroxide — NaOH is used in soap making.
Question 31: Which acid is present in apple?
a) Citric acid
b) Malic acid
c) Oxalic acid
d) Acetic acid
Answer:
b) Malic acid — Apple contains malic acid.
Question 32: Which of the following is used in ant bite treatment?
a) Soap
b) Baking soda
c) Lemon juice
d) Vinegar
Answer:
b) Baking soda — It neutralizes the formic acid in ant bite.
Fill in the Blanks Questions for Class 7 Science Chapter 2 Exploring Substances: Acidic, Basic, and Neutral
1. Acids have a ___ taste.
Answer:
Sour
2. Bases have a ___ taste.
Answer:
Bitter
3. Litmus is a natural indicator obtained from ___.
Answer:
Lichens
4. Turmeric turns ___ in basic solution.
Answer:
Red
5. Vinegar contains ___ acid.
Answer:
Acetic acid
6. Curd contains ___ acid.
Answer:
Lactic acid
7. Oranges contain ___ acid.
Answer:
Citric acid
8. Baking soda is used as an ___ to neutralize stomach acidity.
Answer:
Antacid
9. Tomato contains ___ acid.
Answer:
Oxalic acid
10. Grapes contain ___ acid.
Answer:
Tartaric acid
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